1. Field of the Invention
The present invention generally relates an intercooler for manifold intake air. More particularly compressed charge air from a turbocharged or supercharged engine flows through charge air cooling conduits that are cooled by an ambient air stream that has been cooled by passing around and contacting a refrigerant conduit prior to passing around and contacting the charge air cooling conduits.
2. Discussion of Related Art
Methods of increasing the air or air/fuel mixture density of an engine by increasing the pressure of the intake air stream prior to its entering the engine cylinder can be referred to as “turbocharging” and “supercharging”. A relatively simple and advantageous method of increasing the power generated by the engine is to increase the density of air in the cylinder. Supercharging generally means that the air intake compressor is powered by coupling it to the engine via a belt, chain, etc. Turbocharging commonly means that the engine exhaust stream powers the air intake compressor. Turbocharging is favored over supercharging because current designs are more efficient at harvesting the energy in the exhaust stream. This increased efficiency means that without a significant decrease in fuel economy, turbocharging permits an increase in the engine power output. Charged air means air that is compressed by either a turbocharger or a supercharger.
Since pressure is directly related to heat, as the charger increases the pressure of the intake air stream the charger also increases the intake air stream temperature. Cooler air can be more densely packed so by cooling the intake air stream an additional increase in the intake air stream pressure is further permitted. This additional cooling is generally accomplished through the use of an intercooler.
A basic intercooler would comprise incorporating a heat exchanger into the air stream between the charger and the engine intake manifold. Such a heat exchanger can utilize fins, coils, or a combination thereof to increase the rate at which heat is absorbed and re-radiated into the ambient environment. Even if the placement of the heat exchanger is optimized the ambient air temperature as well as the temperature at the air intake point are uncontrollable variables.
Prior art in this field illustrates intercoolers that are located in the intake air stream between the charger and the combustion chamber where the intercooler contains a heat exchanger that is cooled by the vehicle's air conditioning system. Although this design permits reasonably uniform cooling of the intake air stream, the need for maximum cooling of the intake air stream and the passenger compartment are most likely to occur simultaneously. This has the effect of significantly reducing engine efficiency and erasing power gains from a charger/engine combination. Additionally, failure of the air conditioning system, charger, or engine can result.
From the inception of the age of manufactured motor vehicles, motor vehicles have been increasing in intricacy. With each successive model year the number of features that contribute to vehicle performance, vehicle safety, and operator comfort increases. Features that were once optional are increasingly becoming standard features. Following this trend is a reduction in the amount of space in the engine compartment.
An intercooler is a simple and relatively inexpensive component when compared to a turbocharger or supercharger. Accordingly, using an intercooler would generally be easy to justify because its addition to the operating efficiency of a charger is greater than its size, weight, operation, and expense. Although basic intercoolers appear on many turbocharged vehicles, improved intercoolers have not been utilized for production vehicles. This is due to the fact that the intercooler's size, weight, operation, and expense as compared to using a basic intercooler or no intercooler at all outweigh any improvement to vehicle performance. Thus a need exists for a charge air cooler that is compact and functional no matter where it is mounted in the engine compartment. A further need exists for an improved charge air cooler design that is inexpensive and small, yet still capable of increasing the efficiency of a charger.